In semiconductor devices such as semiconductor diodes, insulated gate bipolar transistors (IGBTs) or insulated gate field effect transistors (IGFETs) a low doping concentration of a base material such as a wafer before front end of line (FEOL) processing serves for realizing a DC voltage blocking requirement of the semiconductor device. Apart from dopants determining an initial doping concentration in the base material, additional impurities may be present, for example caused by a growth process of the base material such as magnetic Czochralski growth of silicon ingots. Front-end-of-line (FEOL) processing may lead to formation of undesired complexes including the additional impurities. One example of such undesired complexes are electrically active complexes, for example nitrogen-oxygen-complexes or CiOi complexes altering a doping concentration or a recombination/generation characteristic of the semiconductor body or of the semiconductor device(s) in the semiconductor body.
It is desirable to provide a method of reducing an impurity concentration in a semiconductor body, a method of manufacturing a semiconductor device and a semiconductor device.